S116 17th ECCMID / 25th ICC, Posters Conclusion: Solar radiation is effective in killing G. lamblia cysts. More assays need to be carried out to find out if it is the UVA produced by the sun or the heat from the sun that is capable of disinfecting these parasites. P523 Evaluation of three commercial assays for the detection of Giardia and Cryptosporidium organisms in stool specimens N. Dauby, C. Moens, S. Mohamed, S. Van den Wijngaert, O. Vandenberg, A. Dediste (Brussels, BE) Objectives: Giardia is known as the most common pathogenic intestinal protozoa in Belgium, yet Cryptosporidium remains frequently under diagnosed. We compared three commercial assays for the detection of Giardia and Cryptosporidium. Methods: Stool specimens were collected from 101 children attending a day care centre located in Brussels. Most of those children presented abdominal complaints and/or diarrhoea since two weeks. Therefore, we wanted to investigate this outbreak in order to exclude a parasitic etiology. Stool specimens were examined according to our specific Triple-Feces-Test (TFT) protocol which consists in 3 samples collected on 3 consecutive days (2 with SAF preservative and one fresh specimen) examined with and without concentration techniques and a permanent staining. In addition, a Rhodamine-auramine O staining for Cryptosporidium is performed on the fresh specimen, with confirmation with Kinyoun carbolfuchsin acid-fast staining. Results obtained with our protocol were compared with those from Prospect Crypto/Giardia ® (ELISA), ImmunoCard STAT ® (IC) and Merifluor ® direct fluorescent- antibody (DFA) commercial tests, each of them performed on the unpreserved stool specimen. Results: Among the 101 children included in the study, 5 and 17 were infected with G. lamblia and Cryptosporidium respectively. The sensitivity of the TFT-protocol was 100% for Giardia which was similar to the sensitivity of the IC and ELISA tests. The specificity of all tested methods was never lower than 97%. The sensitivity of the IC and the ELISA for the detection of Cryptosporidium were 100% and 95.3% respectively compared to 52.9% for the microscopic examination. When we used DFA as screening methods for the diagnosis of Giardia or Cryptosporidium, we found a sensitivity of 80% and 82% respectively. Specificity of the DFA was 100% and 97.6% for Giardia and Cryptosporidium respectively. Conclusion: Microscopy with the TFT protocol is very sensitive for detection of Giardia but less sensitive for detection of Cryptosporidium than the three commercial kits tested. Regarding to our results, we should consider including ELISA or IC tests in our TFT-protocol for a more reliable detection of Crytosporidium. P524 The prevalence of Dientamoeba fragilis infection in patients with suspected enteroparasitic disease in Denmark C.R. Stensvold, M.C. Arendrup, K. Mølbak, H.V. Nielsen (Copenhagen, DK) A study was taken on to describe the prevalence of D. fragilis in patients with suspected enteroparasitic disease in Denmark and the diagnostic relevance of examining preserved rather than unpreserved stool samples. Parasitological examination of paired stool samples from 103 patients was completed using two different techniques: A formol ethyl-acetate concentration technique (FECT) on unpreserved faeces and a permanent staining technique (PST) on faeces preserved with sodium acetate-acetic acid-formalin (SAF). Using SAF-PST and FECT, 25% and 15% of the specimens were parasite-positive, respectively. D. fragilis was detected only in SAF-preserved stools, and 12/103 (12%) patients were shown to harbour the parasite, only two of which were shown also to host other traditionally acknowledged pathogenic parasites. The present study shows that D. fragilis is remarkably prevalent in Denmark. It confirms the relevance of examining SAF-fixed stools of patients with suspected intestinal parasitosis in settings where the examination of freshly passed, warm stools is not an option, since at least 8/10 cases of potentially symptomatic intestinal parasitosis go undetected using conventional concentration and microscopy of unpreserved stools. D. fragilis was seen mainly in patients aged 0-30 and was not associated with travel activity less than 3 months prior to the submission of stools, suggesting endemic occurrence in Denmark. P525 Opportunistic properties of insect microsporidia C. Franzen, S. Fischer, J. Sch¨ olmerich, S. Schneuwly, B. Salzberger (Regensburg, DE) Objectives: Tubulinosema ratisbonensis is a microsporidian pathogen of the fruit fly Drosophila melanogaster belonging to the family Tubulinosematidae. The microsporidia in this family mainly cause infections in invertebrate hosts, but two members of this family, Anncaliia vesicularum and Anncaliia algerae, have been found as cause of infections in humans as well. Moreover, A. algerae could be transmitted to immunodeficient mice and grows in mammalian cell cultures. Thus, the examination of the opportunistic properties of other members of the family Tubulinosematidae is mandatory. Methods: Spores of T. ratisbonensis, isolated from infected fruit flies, were inoculated on mammalian and insect cell cultures and in immunodeficient mice [NMRI (nu/nu)] (n = 24) at different locations (tail, neck, i.p., eye, leg, oral). On day 60 post infection all mice were euthanised and necropsied. Cultures and mice were examined by light microscopy, scanning and transmission electron microscopy, and by PCR and subsequent DNA sequencing. Results: In cell cultures parasite growth was only seen in human lung fibroblasts whereas no growth was seen in Vero cells or insect cell cultures. Transmission electron microscopy showed the typical ultrastructure of T. ratisbonensis and scanning electron microscopy showed oval or slightly pyriform spores with some spores having extruded their polar tubes. Sequencing of PCR-fragments, amplified from infected cell cultures, reveals DNA sequences that were 100% identical with the original T. ratisbonensis rRNA sequence. All 24 mice survived the 60 days study period without clear signs of disease. All examined internal organs were free from microsporidia but limited growth was seen at sites with lower body temperature (tail, leg). Conclusion: As T. ratisbonensis is able to proliferate in mammalian cells and in immunodeficient mice at sites with lower body temperature, it might have opportunistic properties like other members of the family Tubulinosematidae. P526 Clinical significance and frequency of Blastocystis hominis infection in primary school children in Ardabil, Iran (2003) A. Daryani, G.H. Ettehad, N. Barmaki, M. Sharif, A. Abedi, H. Ziaei, H. Alimohammadi (Sari, Ardabil, IR) Objective: There is a dramatic increase in the frequency of Blastocystis hominis infection in association with diarrhoea and distinct clinical symptoms, especially in AIDS patients. The aim of this study was to evaluate the frequency of this parasite, and relate personal data and the presence of signs with the frequency of B. hominis among primary school children. Methods: This cross-sectional study was performed on 1070 school children between 7-13 years old in Ardabil, Iran, 2003. A questionnaire was completed for each child. Stool specimens were collected by stratified random sampling and were examined for presence of B. hominis using direct wet mount and formalin-ether concentration methods. Results: The positive rate of B. hominis was 28.2% (302/1070). A total of 109 cases (10.2%) showed more than five parasites per field at a magnification of 400x. The most common symptoms in children who showed only B. hominis were abdominal pain (49.4%), inappetance (35.8%), and nausea (33%). Conclusion: As B. hominis is quite common among school children, contaminated drinking water is suspected to be the source of infection.